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    <title>Document</title>
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    <script>
        //运算符 &&(and) ||(or)   !(非)
        let a=1,b=2;
        console.log(a&&b); //2
        console.log(a||b);  //1

        let n1=1,n2=0;
        console.log(n1 && n2);//0
        console.log(n1 || n2);//1

        console.log(!n1);//false
        

        console.log("________________________");
        let aa=3;
        let aa1=9;
        let bb=aa||aa1;//3
        console.log(bb); 
    </script>
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